subquery problem

[pizzaluver13]

I have Henry Books as a table.

The columns include: TITLE, PRICE, TYPE(SFI, FIC, MYS), PAPERBACK ('Y' or 'N')

so the question is ...

Part 1 -  For each type of book, list the type and the average price.

 

I don't know how to get average price of a type.

 

Part 2 -consider only paperback books for those types of which the average price is more than $10

 

any help will be appreciated...........

[gizmola]

I have Henry Books as a table.

The columns include: TITLE, PRICE, TYPE(SFI, FIC, MYS), PAPERBACK ('Y' or 'N')

so the question is ...

Part 1 -  For each type of book, list the type and the average price.

 

I don't know how to get average price of a type.

 

Part 2 -consider only paperback books for those types of which the average price is more than $10

 

any help will be appreciated...........

 

Look into GROUP BY.  In your case you want to have groupings by TYPE.  Once you GROUP BY you can use summary functions like AVG().

 

I don't really understand the question for Part 2?

 

 

Is this homework or a test?

[pizzaluver13]

Its practice problems for test review.

the second part of the question builds on the first. So after finding the average price for the types we have to go narrow it down further by if it is a papeback and the average price for the type is greater than $10.

[pizzaluver13]

I got the first part

using

SELECT TYPE, AVG(PRICE)

FROM BOOK

GROUP BY TYPE;

 

 

now I have to do the 2nd part which asks to repeat the above exercise  but consider ONLY paperback books for those types for whcih the average price is more than $10.

[gizmola]

Add a WHERE clause with the 2 criteria you need to be concerned about:

 

WHERE AVG(PRICE) > 10 AND PAPERBACK = 'Y'